地铁多线换乘车站火灾模型实验研究—(1)模型装置设计

为研究地铁网络化运营枢纽车站火灾烟气扩散特征和防排烟技术,根据工程资料和标准规范对典型多线换乘车站进行1∶10火灾实验模型设计,并依据设计方案完成车站模型主体结构和通风排烟系统的搭建,同时在各个防烟分区设计安装温度、流速、烟气浓度和热辐射测量装置,可实现对“T”形、“十”形和“L”形换乘等不同换乘形式车站的火灾场景模拟和危险参数测量。研究结果表明:该模型装置能够开展一系列针对不同换乘形式和通风模式的火灾实验,对于全面揭示大型换乘车站火灾烟气运动规律、验证并优化火灾防排烟设计方法、支撑复杂结构枢纽车站火灾烟气控制技术具有重要意义。     

内窥镜检查在电站锅炉内部检验中的应用

工业内窥镜是电站锅炉内部检验中不可或缺的设备,主要用来对集箱、减温器、受热面管等内部人眼无法观察到的地方进行检验,从而确定承压部件内部是否存在严重影响锅炉安全运行的缺陷.本文通过对锅炉内窥实例进行分析和总结,阐述内窥镜检查在锅炉内检中的重要性并给相关工作人员提供借鉴与参考.     

Effects of water-emulsified fuel on a diesel engine generator’s thermal efficiency and exhaust

Water-emulsified diesel has proven itself as a technically sufficient improvement fuel to improve diesel engine fuel combustion emissions and engine performance. However, it has seldom been used in light-duty diesel engines. Therefore, this paper focuses on an investigation into the thermal efficiency and pollution emission analysis of a light-duty diesel engine generator fueled with different water content emulsified diesel fuels (WD, including WD-0, WD-5, WD-10, and WD-15). In this study, nitric oxide, carbon monoxide, hydrocarbons, and carbon dioxide were analyzed by a vehicle emission gas analyzer, and the particle size and number concentration were measured by an electrical low-pressure impactor. In addition, engine loading and fuel consumption were also measured to calculate the thermal efficiency. Measurement results suggested that water-emulsified diesel was useful to improve the thermal efficiency and the exhaust emission of a diesel engine. Obviously, the thermal efficiency was increased about 1.2 to 19.9%. In addition, water-emulsified diesel leads to a significant reduction of nitric oxide emission (less by about 18.3 to 45.4%). However, the particle number concentration emission might be increased if the loading of the generator becomes lower than or equal to 1800 W. In addition, exhaust particle size distributions were shifted toward larger particles at high loading. The consequence of this research proposed that the water-emulsified diesel was useful to improve the engine performance and some of exhaust emissions, especially the NO emission reduction.

Implications:The accumulated test results provide a good basis to resolve the corresponding pollutants emitted from a light-duty diesel engine generator. By measuring and analyzing transforms of exhaust pollutant from this engine generator, the effects of water-emulsified diesel fuel and loading on emission characteristics might be more clear. Understanding reduction of pollutant emissions during the use of water-emulsified diesel helps improve the effectiveness of the testing program. The analyzed consequences provide useful information to the government for setting policies to curb pollutant emissions from a light-duty diesel engine generator more effectively.     

Reactions of compost-derived humic substances with lead, copper, cadmium, and zinc

Thermodynamic stability constants of the formation of complexes from the reactions of humic substances with various metals are usually used as parameters to judge the reactivities of both humic substances and metals. However, in calculating the thermodynamic stability constants, complicated processes for the acquisition of activities of components in reactions are absolutely inevitable. In this study, we investigated the average conditional concentration quotients of the complexes formed from the reaction of metals with humic substances and the relations of these quotients to thermodynamic stability constants. The characterized humic substances including HA (MW>1,000), FA (MW>1,000), and FA (MW<1,000) extracted from a swine compost were prepared to react with Pb, Cu, Cd, and Zn at 25 degrees C and at pH 4.00 and 6.50. Reactions of HA (MW>1,000), FA (MW>1,000), and FA (MW<1,000) with the four metals were carried out at 1:0.1, 1:0.5, 1:1, 1:5, and 1:10 ligand:metal stoichiometry. The concentrations of the free ions of Pb, Cu, Cd, and Zn in the reaction systems of metal-HA suspensions and metal-FA solutions were measured by anodic stripping voltammetry (ASV). The sequence of the average conditional concentration quotients of the formed complexes from the reaction of humic substances with metals was FA(MW<1,000)>FA(MW>1,000)>HA(MW>1,000), showing the relative reactivities of the fractions of swine compost-derived humic substances. The sequence of reacting metals with humic substances was Pb>Cu>Cd>Zn, which is in good agreement with the sequence reported by judging the thermodynamic stability constants. The average conditional concentration quotients of the formed complexes from the reaction of humic substances with metals were thus useful parameters that can be directly related to thermodynamic stability constants and other parameters.     

Emission of PCDD/Fs and dioxin-like PCBs from metallurgy industries in S. Korea

The metallurgy industry and municipal waste incinerators are considered the main sources of polychlorinated dibenzo-p-dioxin and dibenzofurans (PCDD/Fs) in many countries. This study investigated the emission factors and total emissions of PCDD/Fs and dioxin-like polychlorinated biphenyls (PCBs) emitted from metallurgy industries (including ferrous and nonferrous foundries) in Korea. The toxic equivalency (TEQ) emission factor of PCDD/Fs was the highest for secondary copper production, at 24451 ng I-TEQ/ton. The total estimated emissions of PCDD/Fs from these sources were 35.259 g I-TEQ/yr, comprising 0.088 g I-TEQ/yr from ferrous foundries, 31.713 g I-TEQ/yr from copper production, 1.716 g I-TEQ/yr from lead production, 0.111 g I-TEQ/yr from zinc production, and 1.631 g I-TEQ/yr from aluminum production. The total estimated annual amounts of dioxin-like PCBs emitted from these sources were 13.260 g WHO-TEQ/yr, comprising 0.014 g WHO-TEQ/yr from ferrous foundries, 12.675 g WHO-TEQ/yr from copper production, 0.170 g WHO-TEQ/yr from lead production, 0.017 g WHO-TEQ/yr from zinc production, and 0.384 g WHO-TEQ/yr from aluminum production. The highest emission factor was found for secondary copper smelting, at 9770 ng WHO-TEQ/ton.     

中性点不接地电网中单相接地故障的分析及处理

阐述了中性点不接地电网中单相接地的特点,并分析了用绝缘监视装置和小电流接地选线装置查找故障的利弊,以及目前小电流接地选线技术可靠性差的原因.     

BP网络应用于大气环境监测点的优选

为了对大气环境监测点进行优化选择 ,以大气质量分级标准为训练样本 ,构造BP网络进行训练 ,用训练好的BP网络对某地的大气环境监测采样点进行了优选 ,并与物元分析法优选结果进行比较。结果表明 ,BP网络用于环境测点优选具有较好的客观性和应用性     

扬州市不同行政区域空气重金属污染评价

采用活藓监测法,选择广泛分布的小羽藓为材料,对扬州市区、高邮市、仪征市、宝应县4个区域空气中Pb、Zn、Cd、Cr、Ni、Zn、Hg 7种重金属元素污染情况进行监测.利用污染因子分析法、内梅罗综合指数分析法及重金属污染潜在生态风险评价法对不同区域空气重金属危害等级进行评价.结果表明:Zn、Pb、Cd元素主要污染地区为扬州市区,Cu元素主要污染地区为仪征市,Ni、Hg元素主要污染地区为宝应县,Cr元素主要污染地区为高邮市.4个区域空气重金属均处于重度污染水平,存在强生态风险.就整体而言,7种重金属元素中Cd、Zn、Hg为主要污染元素,污染情况最为严重,而Cu、Ni污染程度相对较轻.区域间空气重金属污染特征差别显著,制造业与港口航运发达的南部仪征市、江都区等地比以农业为主的北部宝应县污染重,污染程度由高到低为扬州市区仪征市高邮市宝应县.     

GB/T28001-2011 4.3.1要素关键点分析

从危险源辨识和风险评价程序、方法和控制措施的确定几个方面,对GB/T28001-2011《职业健康安全管理体系要求》的4.3.1要素进行了关键点分析.     

土著微生物修复铬(Ⅵ)污染土壤的条件实验研究

根据铬(Ⅵ)污染土壤中筛选出的土著微生物初步解毒实验结果,将土著菌种制成六价铬还原菌剂,通过时间、温度、菌量、pH值、有机质用量等单因素条件实验,发现温度和有机质含量对六价铬还原影响显著,在上述各项较佳条件下施用该菌剂1个月后,对于浸出液六价铬浓度范围从10-55mg/L的污染土壤,六价铬的还原效果都可达到90%以上,高于化学法,这说明该菌剂可有效应用于六价铬土壤的生物修复。